Weighing scale



N. E. HART WEIGHING SCALE July 3, 1951 3 Sheets-Sheet 1 Filed May 2, 1944 INVENTOR.

1T W 5 W. Z

3 Sheets-Sheet 2 N. E. HART WEIGHING SCALE July 3, 1951 Filed May 2, 1944 INVENTOR. Norman E. Harv BY ATTORNEYS do 0 2a n N. E. HART WEIGHING SCALE July 3, 1951 Filed May 2, 1944 3 Sheets-Sheet 5 INVENTOR.

H z m N ATTORNEYS Patented July 3, 1951 WEIGHIN G SCALE Norman E. Hart, Toledo, Ohio, assignor to Toledo Scale Company, Toledo, Ohio, a corporation of New Jersey Application May 2, 1944, Serial No. 533,756

2 Claims.

This invention relates to weighing scales and in particular to weighing scales, known as counting scales, which are calibrated to indicate the number of pieces in the load rather than the weight of the load.

The principle of counting by weight is not new. Scales have been designed for this purpose and these scales may be divided into two classes.

Scales of the first of these classes, known as ratio counting scales, employ a small number of parts in a sample load receiver to counterbalance a relatively large group of parts in a main load receiver. The number of pieces or count is obtained from the known ratio of the scale and the number of parts in the sample load receiver. Scales of the second class, known as direct reading counting scales, employ means to change the calibration of the scale according to the weight of the parts being counted.

The present invention relates to improvements in a counting scale of the second class which materially simplify the scale and increase its field of usefulness.

The object of this invention is to provide a counting scale which is readily portable and is easily adjusted for use.

Another object is to provide a novel chart mounting which allows the calibration of the scale to be readily adjusted for changes in the weight of the parts being counted without disturbing the zero adjustment.

A further object is to provide, in a weighing scale whose calibration is adjusted by moving its chart, a second chart adapted to indicate the change in calibration of the weighing chart with movement thereof.

A still further object is to provide means to firmly mount the base of a weighing scale in a carrying case while still allowing the base to be readily leveled.

These and more specific objects and advantages are apparent from the following description in which reference is made to the accompanying drawings.

In the drawings:

Figure I is a front elevation of a portable counting scale as mounted in a carrying case. A portion of the case is cut away to reveal the scale.

Figure II is a fragmentary front elevation of the scale shown in Figure I at an enlarged scale and with some of the parts broken away to reveal the construction of the chart moving mechanism.

Figure III is a horizontal section taken along the line III-III of Figure II.

Figure IV is a vertical section taken substantially along the line IV-IV of Figure II.

Figure V is an enlarged section taken substantially along the line VV of Figure IV.

Figure VI is a fragmentary plan of the fulcrum portion of the lever.

Figure VII is anenlarged fragmentary plan of the chart mounting slide taken along the line VIIVII of Figure II.

Figure VIII is an enlarged end elevation of the leveling screw, parts being shown in section.

Figure IX is a fragmentary front elevation showing a counting scale equipped with a straight line chart and a secondary chart for indicating the position of the first chart.

In a counting scale designed to count parts of uniform weight and having a chart graduated according to the weight of the parts, any change in weight of the parts of a particular lot with respect to the standard weight of that part results in an error which must be allowed for in determining the total count.

This invention provides means for compensating for the variation in weight by changingthe calibration of the scale in proportion to the change in weight. This is accomplished by moving the chart either toward or away from the axis about which the indicator is pivoted. Because the indicator assumes definite positions for definite weights, the motion of the chart toward or from the indicator axis changes the efiective calibration and thus provides an easy method for compensating for small variations in the weight of the pieces to be counted. Because it is desirable, when such a calibration is made, that the zero of the scale remain unchanged the chart is moved along a line parallel to the index portion of the indicator when the indicator is at the zero position.

The invention, further, provides a fiexure plate for mounting one end of the base of the scale from the bottom of the carrying case and an adjusting screw at the other end of the base. This construction has the advantage that the weighing mechanism is always firmly mounted within the case but is yet capable of being adjusted for any out of level condition of the surface on which the case is resting.

These improvements are embodied in a portable scale designed to count, by weight, large numbers of small stamps or other similar items. The nominal weight of the stamps is a fairly constant quantity although material variations occur from lot to lot. One cause of variation is changes in atmospheric humidity. The scale is conditioned for counting these stamps by first leveling the base then placing a quantity of stamps, which were previously hand counted, in the load receiver and adjusting the chart position until the indication agrees with the hand count. This operation, while it takes a few moments, compensates for all of the variables encountered in a particular group of stamps.

These advantages are attained in the specific example illustrated in the drawings. This example is a portable counting scale enclosed in a carrying case it! and comprises a base ll, an A-shaped stand 12 erected on the base H, a lever 13 pivotally mounted at the top of the stand [2, an indicator i l attached to the lever l3 and a chart 3-5. The top of the stand i2 is provided with a forwardly extending horizontal section it, and a portion ii depending from the forward end of the horizontal section it. The depending portion ll and the upper part of the stand it immediately therebehind bored to receive a pair of ball bearings iii. The lever [3, provided with trunnions is pivotally supported in the bearings it.

The lever is is provided near one extremity with a load pivot iii. A stirrup 21 depending from the load pivot supports a scoop-shaped load receiving pan When not in use the pan 22 is removed from the stirrup 2i and slipped behind a pair of cleats attached to the rear wall of the case it.

The end of the lever is opposite that con taining the load pivot 2c is formed as a hollow shell open at the bottom. In this hollow shell a counterweight 2% is adjustably mounted on a leaf 25 secured to the lever by a screw 26.

A pair of rubber headed screws and 28 are fitted into the stand 52 and act as stops for the lever l3.

A dashpot mounted on a bracket extending from the stand 52 is provided to control the oscillations or" the lever resulting from changes of load. A connected the piston of the dashpot 29 has its upper end flattened and transversely drilled. The tongue thus formed fits in the bifurcated end of an h -shaped arm 32 extending outwardly and. downwardly from a boss 33 in the lever i i. A pin 3t, forming part of a clip fitted through horizontal holes in the of the arm and the hole in the dashpot stem at thereby pivotally connecting the dashpot and lever. Spring arms forming part of the clip prevent the pin from working loose.

The dashpot is fitted with cap having an axial hole to accommodate .ne stem 3!. Be cause the scale is portable an auxiliary cap 37'! is provided to seal the dashpot while the scale is being transported. The cap a? has an axial recess adapted to over the stem 3% and is applied by merely unhooiring the stem at from the arm 32 and screwing the cap it? into the cap 3%.

The indicator is at its up er end secured to a yoke rotatably moun ed on the shanks of the trunn ons A pair or screws {is threaded vertically t ough the bottom or the yoke 38 engages the lever B and provides means for ad justing and maintaining the ar position of 1. the indicator it with respect to the lever H3.

The lower end of the indicator is is provided with a knife blade index at to cooperate with a series or" indicia ll carried on the chart ill. The chart i is rigidly moun d on a slide 32 which in turn s slidably mounted in cross bers 63 and as the stand A pair of screws passing through slots is in the slide holds ie slide in notches in the cross members. The notches in the cross members and i l are so located that the motion of the chart i5 is along a line parallel to the line joining the center of the beariit and the zero indicium of the series of indicia ill on the chart to. Thus, regardless of the position of the chart, the zero reading of the chart is not changed.

The chart I5 is moved into position by an operating lever :il pivotally mounted on a screw 48 threaded into one of the legs of the stand I2 and engaging a pin is extending rearwardly from the slide 42.

A flexible, yet firm, spring hinge 5i is attached to the bottom of the case as and to one end of the base Ii. The other end of the base ll is suported by a leveling screw it. The leveling screw iii is locked in adjusted position by a wing nut 52. The lower end of the leveling screw 5! is provided with an oval head 53 which is held between plates 5:5. and secured to the bottom of the case H3. The leveling screw 56 is rotated by turning a knurled knob at its upper end until a spirit level til attached to the base ll indicates that the base is level.

While the spring hinge 5c is shown as being generally horizontal, it may also be formed so that its center section is substantially vertical. In this particular example the weights of the loads being weighed are so insignificant with respect to the weight of base ii and the weighing structure that the deflection of the flat spring hinge with changes load is not appreciable. If the loads being weighed are of the same order of magnitude as the weight of the structure the hinge 55! is formed with its central portion vertical so that it acts as a co1- urnn rather than cantilever The only other requirement is that the hinge iii} be capable of accommodating the maximum range of adjustment or the leveling screw 5i without exceeding its elastic limit.

In the operation of this scale, which was specifically designed for counting small paper stamps of generally constant weight, the opera tor first hand counts a sample approximately equal to the scale capacity, places them on the scale, and by means or" the lever i'i adjusts the position of the chart it; until the indication of the knife blade index on the indicia ti agrees with the hand count. The is thus adjusted for the type and condition of stamps represented by the sample and the operator may then continue to count remaining stamps by merely placing them in the scoop and reading the count from the indicia iii.

The indicia M are arranged along the arcuate path described by the index it. Because the scale is of the so-called hook pull variety the indicia 4! are not equally spaced. Therefore, a slight error in indication is introduced as the chart is moved away from its midposition. This error may be eliminated by arranging the indicia along a straight line as is shown in Figure IX. In this example, in which only the essential parts of the chart and indicator are shown, the scale comprises a base I la, an A-shaped stand i2a erected on the base I la, an indicator Ma including a knife blade index 49a depending from a lever, not shown, and a chart Mia. The chart 5a bears indicia 41a disposed along a straight line along the path of the index liia. A slide ti2a, carrying the chart Ida, is slidably mounted on cross members in the stand 82a to allow the chart l5a to move parallel to the line connecting the zero indicium of the series of indicia i i a and the fulcrum axis of the lever. A secondary indicator 58 attached to the slide 52a cooperates with indicia 59 printed on a secondary chart Gil attached to the stand i211. The indicia 59 are arranged to indicate the percentage of increase or decrease in the value of the indicia 4 la produced by the translatory motion or" the chart Hia.

The indicia 59 as shown in Figure IX indicate the percentage deviation in the weight of the sample from the standard weight for which the scale is adjusted. Thus if, when a hand count is made and the lot so determined is placed in the scale, the chart [5a must be lowered to secure a corresponding indication the parts being counted are underweight and the indicia 59 indicate the percentage underweight. Likewise, if the chart l5a must be raised to secure corresponding indications the particular sample being weighed is overweight.

The disclosed means for adjusting the scale calibration by indicated amounts is also useful for determining the moisture content of a material, for weighing out quantities of material to a definite final or dry weight when the substance is known to have a certain percentage of moisture, for adding a predetermined amount of material to a load on the scale, and other similar applications.

When the scale is used as a moisture tester, the sample is first weighed with the chart in its zero position; i. e. its normal, or 100% reading point; and its weight noted. The sample is then dried in an oven or by some other means and then reweighed. This time the chart is moved down to get the same weight reading as before. The distance the chart must be moved is proportional to the percentage of moisture in the original sample. The secondary chart can be calibrated directly in terms of moisture content.

If it is desired to weigh out to meet a predetermined processed weight definite quantities of a material which is known to experience a certain percentage shrink in weight during processing, such as bread before baking, the chart is set for the percentage change and the scale will then indicate the final weight when the raw material is placed on the load receiver. It thus becomes a simple matter to weigh out the required quantity.

Another application is in the meat packing industry where hams are pickled by pumping brine into the arteries. It is desirable to add an amount of brine equal to a definite proportion of the weight of the ham. This is accomplished by weighing the ham with the chart in its normal position, then shifting the chart to the desired percentage and adding brine until the original weight indication is again reached. If desired, two charts can be used to avoid changing the chart position for each ham.

This scale is also well adapted for compounding materials. For example, suppose the formula calls for ninety percent of ingredient A, six per cent of ingredient B, four percent of ingredient C, and the total is to be D units of weight. This is easily compounded on this scale by first setting the chart for ten percent under (ninety percent of weight) and weighing in D units of ingredient A, then setting the chart for four percent under (ninety plus six percent of weight) and adding ingredient B until the indicator again indicates D units, and finally setting the chart at zero and adding ingredient C until the indicator again indicates D units. Because the scale reads directly in units of weight when set at Zero percent the total of ingredients A, B and C so obtained is D units of weight. Alternatively, the formula may give the amounts of some ingredients as percentages of the basic ingredient. In this case E units of the basic ingredient are first weighed with the chart set at zero percent. Then the chart is raised to the percentage of the next ingredient and that ingredient added until the in dicatcr indicates E units. The chart is then raised an additional amount corresponding to the percentage of the next material and that material is added. Thus a formula given in percentages may be compounded without calculation.

These illustrative examples are intended mere- 1y as a guide in using the invention and not its limits of usefulness.

Having described my invention, I claim:

1. In a device of the class described in combination, a weighing lever having a fulcrum pivot and a load pivot defining a pivot line that is generally horizontal at the midposition of the lever travel, an indicator attached to the lever, the indicator having a straight index portion of substantial length extending radially from the fulcrum of the lever, a chart mounted parallelly adjacent the path of the index portion of the indicator and having indicia equally spaced along a straight line that is perpendicular to the index portion when said pivot line is horizontal, guide means extending parallel to a line through the zero indicium of the chart and the fulcrum pivot for supporting the chart and mechanism for moving the chart along the guide means.

2. In a device of the class described, in combination, a weighing lever having a fulcrum pivot and a load pivot defining a pivot line that is horizontal near the midposition of the lever travel, an indicator attached to the lever and having a straight index portion of substantial length extending radially from the fulcrum of the lever, a chart positioned along the path of the index portion and having indicia equally spaced along a straight line that is perpendicular to the index portion when the pivot line is horizontal, guide means that support the chart for translation along an inclined line passing through the fulcrum of the lever and the zero load indicium of the chart, a chart index mounted on the chart and a second chart extending along the path of the chart index to cooperate with the chart index to indicate the displacement of the first mentioned chart.

NORMAN E. HART.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,258,009 Jacobs Mar. 5, 1918 1,551,726 Birk Sept. 1, 1925 1,743,354 Johnson Jan. 14, 1930 1,757,766 Ferguson et al May 6, 1930 1,825,848 Benjamin Oct. 6, 1931 1,941,981 Fontaine Jan. 2, 1934 2,074,384 Gattoni Mar. 23, 1937 2,177,669 Martin Oct. 31, 1939 2,277,700 Guibert et a1 Mar. 31, 1942 2,308,044 Brown et a1 Jan. 12, 1943 2,316,230 Enders Apr. 13, 1943 OTHER REFERENCES A Treatice on Weighing Machines by George A. Owen. Pub. 1922 by Charles Griffin & 00., Ltd. 

